Tunable microring resonators using light-activated functional polymer coatings.

Abstract

We demonstrate tunable microring resonators (TMRs) based on light-activated functional polymer coatings deposited on glass optical fibers. TMRs were fabricated using two layers of polydimethylsiloxane-based compounds: one incorporating an azobenzene dye and one using a fluorescent ytterbium and erbium-doped sodium yttrium fluoride powder. The latter yields a photoluminescent composite producing green up-conversion emission under infrared pumping. This visible emission triggers photoinduced birefringence effects in the azobenzene layer, thereby modifying the spectral features of the TMR devices. The shift in the resonance peaks as a function of pump power is linear, yielding a tuning range of 1.3 nm. Aside from the observed photoinduced effects, we also discuss the photothermal effects involved in the tuning mechanism.